Latex emulsions of resins may be produced using PIE in which resins are dissolved in a mixture of water and organic solvent(s) (e.g., methyl ethyl ketone (MEK), isopropyl alcohol (IPA) or both) to form a homogenous water-in-oil (W/O) dispersion (i.e., water droplets dispersed in a continuous oil matrix). Subsequently, water is added to convert the dispersion into stable oil-in-water (O/W) latex (water as the continuous phase).
Organic solvent(s) is(are) removed (for example, by vacuum distillation), the resin particles can be washed, and surfactant and/or other reagents, such as, preservatives, may be added to provide a stable latex with high solid content. Such a latex may be used, for example, in emulsion aggregation (EA) methods for the production of toner particles (see, e.g., U.S. Pat. Nos. 5,853,943, 5,902,710; 5,910,387; 5,916,725; 5,919,595; 5,925,488, 5,977,210 and 5,994,020, and U.S. Pub. No. 2008/0107989, the entire disclosure of each of which hereby is incorporated by reference in entirety.)
Conventional pigments generally are hydrophobic and have to be dispersed in water with a surfactant to produce homogeneous dispersion for use in EA. But the dispersion of dry pigments increases cost, increases energy demand, prolongs cycle time and increases toner production cost.
It would be advantageous to develop processes that enhance latex production and toner production while reducing manufacturing cost that avoids the need to produce pigment dispersions.